1. Field of the Invention
The present invention relates to a heat engine in which spaces that retain working gases with different temperature ranges from each other are provided, and a regenerator is provided as a boundary between the temperature ranges. In such a heat engine, heat and motive energy are exchanged by using volumetric changes of a high-temperature space and of a low-temperature space, which are located on either side of the regenerator, and by using a transfer of working gases between the spaces.
2. Description of the Related Art
A Stirling Cycle is characterized by its capability of running on not only a combustion heat source but also other heat sources with various temperature differences, such as waste heat and solar heat. Obtaining maximum output from heat sources with various temperature ranges requires an optimization of balance between the volumetric change of working gas and gas flow passing through a regenerator in accordance with the temperature difference.
Specifically, use of a heat source with a smaller temperature difference, such as waste heat and solar heat, needs a larger ratio of gas flow passing through the regenerator compared to the volumetric change. The reason is as follows. A source of output of the Stirling Cycle in this case is a rise in gas pressure at the time when the gas passes through the regenerator. A smaller temperature difference renders a smaller rise in pressure relative to the gas flow passing therethrough. Accordingly, obtaining maximum output from a heat source with a smaller temperature difference needs an increase in gas flow passing through the regenerator relative to the volumetric change in comparison to gas flow in a case of using a heat source with a larger temperature difference.